Fuzzy inference means has heretofore been utilized in a detecting road surface frictional coefficient in automotive applications as shown in U.S. Pat. No. 5,229,955 to Nishiwaki et al.
U.S. Pat. No. 4,843,342 to Takahashi et al. discloses an antiskid brake control system using fuzzy logic rules. It requires a wheel speed input and sensor for vehicle body behavior (the exemplary system uses acceleration). In contrast, the present system hereinafter described utilizes only wheel speed and a clock; all other quantities are derived therefrom. U.S. Pat. No. 5,001,640 to Matsumoto et al. suggests a servo control system consisting of a controlled object, an actuator for controlling it, a sensor monitoring the controlled quantity, and a control device employing fuzzy reasoning. It is implied that the inputs are limited to reduce the required calculations and improve the response time of the system. The exemplary system in Matsumoto et al. is an antiskid brake control system for an automobile. However, instead of monitoring only the controlled quantity as hereinafter described, the system shown in Matsumoto et al. uses both wheel speeds and applied hydraulic brake pressures as inputs.